When mentioned in the text, only last names of authors are used. For a 2-author reference, list both surnames; for references with more than 2 authors or authors and a group, include the first author’s surname followed by “et al”.
Superscript numbers
The numbers in text are in superscript1 and occur at the end of the clause in which you used the information. They occur outside “quotation marks,”2 commas,3(parentheses)4 and full stops.5 However, they occur inside semicolons6; and colons7:
Do not leave a space between the last letter or punctuation mark and the number.
Re-use numbers for the same citation
Citations should be numbered sequentially – that is, the first source you cite is 1, the second source is 2 and so on.
However, once you have given a source a number, it will keep that number throughout your paper. So, if you use your first source again, no matter how often you use it, it is still 1.
Within the medical sciences, direct quotes are only used if the exact wording is important. Generally, you should be paraphrasing your research. When paraphrasing, it is not standard practice to use page numbers, but they can be used if you feel it is necessary for clarification.
However, if you do need to refer to the exact wording used by the authors, you must put the quote in "quotation marks" and use a page number next to the in-text citation. The page number should be placed in parentheses directly after the reference number, with no space within the superscript: 1(p6).
Example:
Rey's support of the Mad Dog theory is equivocal, and he states "I’m not defending Mad-doggery because I believe it."3(p125)
Use commas to show that more than one work is being cited, and use hyphens for several works that would be numbered sequentially:
Example:
These side effects can have implications for the patient's mental health, as numerous studies have shown.1,3,6-9
The reference list follows the order of the numbers used in the text. The first source cited in the text is 1 and the reader will look for number 1 in the reference list to find the full citation; the fifth source you use is 5 and the full citation is listed at number 5 in the reference list (and so on).
Notes:
Avoid placing a superscript reference citation immediately after a number or an abbreviated unit of measure to avoid any confusion between the superscript reference citation and an exponent.
Avoid: The 2 largest studies to date included 262 and 183 patients.
Better: The 2 largest studies to date included 26 patients2 and 18 patients.3